iotests: Add test for failing qemu-img commit

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170616135847.17726-1-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2 files changed